Paula Creamer, who led entering final round, managed a 1-under 71 to take second place at 11-under-par 277. Rosie Jones, a two-time champion here, closed with a 4-under 68 to end in third place at minus-10.
Ochoa, a two-time winner in 2004, parred her first four holes before sinking a birdie on No. 5 to move to 9 under. The 23-year-old came back with a birdie on the eighth.
Around the turn, Ochoa stumbled to bogey on the 10th. Creamer, who was playing with Ochoa, birdied the 11th at Locust Hill Country Club to get to 14 under and move five strokes clear of the Mexican.
Ochoa, however, caught fire down the stretch. She dropped her second shot within 3 feet for birdie on the 12th, and then made it two in a row with an 8-foot birdie putt on the next.
'I made that birdie on 12 and that was the beginning of all my birdies,' Ochoa said. 'That gave me good momentum and you know it is all about having confidence out there.'
Ochoa rolled in a 12-footer for birdie at 14 to get within one of Creamer. She then birdied the 15th to tie for the lead, and rolled in a 5-footer for birdie on the par-4 16th to move one clear of Creamer.
Ochoa, who led after the second round, parred No. 17, but her lead moved to two as Creamer three-putted for bogey from the back fringe. Ochoa drained a curling 35-foot birdie try at the last to secure her third LPGA Tour crown.
'There are no words to explain that run,' said Ochoa, who earned $225,000 for the win. 'I was just thinking I want to make this one and I want to win, I want to win. I was just trying to stay positive the whole back nine.'
Creamer, who won the Sybase Classic four weeks ago in New Rochelle, bogeyed the first. She came right back with consecutive birdies from the second to move to 11 under.
The 18-year-old made the turn at 13 under after birdies on six and eight. Creamer birdied the 11th, but tripped to a bogey on 12. After her bogey on 17, she three-putted for bogey on the last to finish four back. Her 11-under total was good enough for her fourth top-five finish of 2005.
'She just played absolutely fantastic. There is nothing else she could do except make birdie and she did it,' Creamer said of Ochoa. 'It's best to be beat like that. She's a true champion. I knew it was going to be tough coming down the finish, but I tried my hardest and that's all I could have done.'
Laura Diaz closed with a 4-under 68 to end at 5-under-par 283. She was joined there by Dorothy Delasin (70) and first-round leader Becky Morgan (74).
Mi Hyun Kim, a two-time runner-up here, ended in a tie for 10th at 4-under- par 284. She finished alongside Candie Kung, Tina Barrett, Patricia Baxter-Johnson, Maria Hjorth and Catriona Matthew.
Kim Saiki, the 2004 champion, ended in a tie for 34th at 3-over-par 291 after a final-round 73.